(a) Field of the Invention
The present invention relates to a method and system for efficiently controlling an air flow supplied to a vehicle fuel cell.
(b) Description of the Related Art
In operation of a fuel cell system, air flow is a major factor that affects the performance of a stack and the efficiency of the system.
The main purpose of air supply control is to minimize air supply while maintaining optimal stack performance. Air supply quantity is determined by a current quantity and a stoichiometric ratio, which can be determined by an air flow controller. The air flow controller can supply a minimum air flow to a fuel cell in order to maintain cell voltage uniformity in states other than a stop state.
A minimum air flow can be supplied to the fuel cell according to current in the range of 30 to 50 A, and thus flooding in the fuel cell can be prevented and voltage uniformity can be obtained.
However, when supply of current in the range of 30 to 50 A to the fuel cell is maintained for a long time in order to supply a minimum air flow, air exceeding a necessary air flow is supplied to the fuel cell, resulting in air supply time increase.
When air supply time increases, the inside of the fuel cell stack is dried, causing an air blower to consume more energy than necessary.